| A | B |
|---|
| NOWL | normal operating water level |
| MAWP | maximum allowable working pressure |
| PSI | pounds per square inch |
| PSIA | pounds per square inch absolute pressure |
| lbs/hour | pounds per hour |
| GPM | gallons per minute |
| H | hydrogen |
| C | carbon |
| O2 | oxygen |
| CO2 | carbon dioxide |
| H2O | water |
| N2 | nitrogen |
| BHP | boiler horsepower |
| HRT | horizontal return tubular boiler |
| OSHA | Occupational Safety and Health Administration |
| EPA | Environmental Protection Agency |
| ASME | American Society of Mechanical Engineers |
